<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>九宫格</title>
    <style>
        div{
            float: left;
            width: 200px;
            height: 200px;
            text-align: center;
            line-height: 200px;
            background-color: white;
            margin: -3px;
            border: solid 6px red;
            font-size: 30px;
        }
        div.container{
            width: 618px;
            height: 618px;
            background-color: red;
            float: none;
            border: solid 0px;
        }
        
    </style>
</head>
<body>
    <div class="container">
        <div>1</div>
        <div>2</div>
        <div>3</div>
        <div>4</div>
        <div>5</div>
        <div>6</div>
        <div>7</div>
        <div>8</div>
        <div>9</div>

    </div>
</body>
</html>